Problem: $-3cd + ce - 6c + 5 = 5d + 7$ Solve for $c$.
Solution: Combine constant terms on the right. $-3cd + ce - 6c + {5} = 5d + {7}$ $-3cd + ce - 6c = 5d + {2}$ Notice that all the terms on the left-hand side of the equation have $c$ in them. $-3{c}d + 1{c}e - 6{c} = 5d + 2$ Factor out the $c$ ${c} \cdot \left( -3d + e - 6 \right) = 5d + 2$ Isolate the $c$ $c \cdot \left( -{3d + e - 6} \right) = 5d + 2$ $c = \dfrac{ 5d + 2 }{ -{3d + e - 6} }$